On Wednesday 15 October 2014 15:21:18 Tim Small wrote: > On 15/10/14 14:12, Peter Wu wrote: > > [ blkdiscard vs hdparm --security-erase] How does this compare. The goal is > > to erase the contents of an previously used SSD to improve performance. > > > > When you use blkdiscard, the SSD (assuming a SATA SSD) will receive an > ATA TRIM command, whereas hdparm --security-erase will issue an ATA > SECURITY ERASE UNIT command. > > What the drive then actually does is dependant on the implementation > details of that particular SSD's firmware. > > In general, I would expect the performance gain from TRIMing the entire > drive to be either the same-as, or possibly less-than the gain from > SECURITY ERASE. For a sane firmware implementation I'd expect them to > have the same effect on performance. Firmware implementations are not > always sane. The names suggest that TRIM is for marking sectors for garbage collection while SECURITY ERASE tries a bit harder. From the runtime performance point of view, I would expect that S.E. is at least as fast as TRIM as no more garbage needs to be collected at a later point. From a durability PoV, not so sure, it could be that S.E. overwrites all blocks (or not). Anyway, I have not read into the details and unless the standards (and manufacturers) can guarantee certain behavior, it will likely vary between device models. Thank you for your reply! -- Kind regards, Peter https://lekensteyn.nl -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
